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	<div id="winchm_template_title">!ioctldecode</div>
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	<div id="winchm_template_content"><div id="mainSection"><p>The <b>!ioctldecode</b> extension displays the <i>Device Type</i>, <i>Required Access</i>, <i>Function Code</i> and <i>Transfer Type</i> as specified by the given IOCTL code. For more information about IOCTL control codes, see  Defining I/O Control Codes.</p>
<pre class="syntax">
    <b>!ioctldecode </b><i>IoctlCode</i> 
</pre>
<h2><a id="ddk__ioresdes_dbg"></a><a id="DDK__IORESDES_DBG"></a>Parameters</h2>
<p></p>
<dl>
<dt><a id="_______IoctlCode______"></a><a id="_______ioctlcode______"></a><a id="_______IOCTLCODE______"></a>       <i>IoctlCode</i>      </dt>
<dd>
<p>Specifies the hexadecimal IOCTL Code. The <a href="#Bookmark2366"><b>!irp</b></a> command displays the IOCTL code in its output. </p>
</dd>
</dl>
<h3><a id="DLL"></a><a id="dll"></a>DLL</h3>
<table>
<tr>
<td>
<p>
          Kdexts.dll
         </p>
</td>
</tr>
</table>
<p> </p>
<h3><a id="Additional_Information"></a><a id="additional_information"></a><a id="ADDITIONAL_INFORMATION"></a>Additional Information</h3>
<p>To see information on the IOCTL, we first locate an IRP of interest. You can use the <a href="#Bookmark2367"><b>!irpfind</b></a> command to locate an irp of interest.</p>
<p>Use the <a href="#Bookmark2366"><b>!irp</b></a> command to display information about the irp.</p>
<div class="code"><span codelanguage=""><table>
<tr>
<th></th>
</tr>
<tr>
<td>
<pre>0: kd&gt; !irp ffffd581a6c6cd30
Irp is active with 6 stacks 6 is current (= 0xffffd581a6c6cf68)
No Mdl: No System Buffer: Thread 00000000:  Irp stack trace.  
     cmd  flg cl Device   File     Completion-Context
[N/A(0), N/A(0)]
            0  0 00000000 00000000 00000000-00000000    

                                                Args: 00000000 00000000 00000000 00000000
[N/A(0), N/A(0)]
            0  0 00000000 00000000 00000000-00000000    

                                                Args: 00000000 00000000 00000000 00000000
[N/A(0), N/A(0)]
            0  0 00000000 00000000 00000000-00000000    

                                                Args: 00000000 00000000 00000000 00000000
[N/A(0), N/A(0)]
            0  0 00000000 00000000 00000000-00000000    

                                                Args: 00000000 00000000 00000000 00000000
[N/A(0), N/A(0)]
            0  0 00000000 00000000 00000000-00000000    

                                                Args: 00000000 00000000 00000000 00000000
&gt;[IRP_MJ_INTERNAL_DEVICE_CONTROL(f), N/A(0)]
            0 e1 ffffd581a5fbd050 00000000 fffff806d2412cf0-ffffd581a5cce050 Success Error Cancel pending
                       \Driver\usbehci        (IopUnloadSafeCompletion)
                                                Args: ffffd581a6c61a50 00000000 0x220003 00000000
</pre>
</td>
</tr>
</table></span></div>
<p>The third argument displayed, in this case <i>0x220003</i>, is the IOCTL code. Use the IOCTL code to display information about the IOCTL, in this case <b>IOCTL_INTERNAL_USB_SUBMIT_URB</b>.</p>
<div class="code"><span codelanguage=""><table>
<tr>
<th></th>
</tr>
<tr>
<td>
<pre>0: kd&gt; !ioctldecode 0x220003

IOCTL_INTERNAL_USB_SUBMIT_URB

Device Type    : 0x22 (FILE_DEVICE_WINLOAD) (FILE_DEVICE_USER_MODE_BUS) (FILE_DEVICE_USB) (FILE_DEVICE_UNKNOWN)
Method         : 0x3 METHOD_NEITHER 
Access         : FILE_ANY_ACCESS
Function       : 0x0</pre>
</td>
</tr>
</table></span></div>
<p>If you provide an IOCTL code that is not available, you will see this type of output. </p>
<div class="code"><span codelanguage=""><table>
<tr>
<th></th>
</tr>
<tr>
<td>
<pre>0: kd&gt; !ioctldecode 0x1280ce

Unknown IOCTL  : 0x1280ce 

Device Type    : 0x12 (FILE_DEVICE_NETWORK)
Method         : 0x2 METHOD_OUT_DIRECT 
Access         : FILE_WRITE_ACCESS 
Function       : 0x33</pre>
</td>
</tr>
</table></span></div>
<p>Although the IOCTL is not identified, information about the IOCTL fields are displayed. </p>
<p>Note that only a subset of publically defined IOCTLs are  able to be identified by the <b>!ioctldecode</b> command.</p>
<p>For more information about IOCTLs see Introduction to I/O Control Codes.</p>
<p>For more general  information about IRPs and IOCTLs, refer to <i>Windows Internals</i> by Mark E. Russinovich, David A. Solomon and Alex Ionescu.
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